Albinism in Sharks

The relative darkness or lightness of a given shark species may vary
enormously among individuals. A few species of sharks, such as the Dusky
Smoothhound (Mustelus canis) can gradually change their color after
moving from one habitat to another. Other species, such as the Blacktip Shark (Carcharhinus
limbatus), may temporarily lose virtually all their pigmentation during
"whitings", which are poorly understood blooms of shelled protozoans
called "coccolithophores". But true albinos — resulting from a blocked
gene crucial to pigment formation — seem to be very rare among sharks. Below is
a list of all shark species in which partial or full albinism is known to date:

Why is albinism so rare among sharks? Probably because being snow white makes
them highly visible to both prey and predators, so it is unlikely they would
long survive. Indeed, most albinistic shark specimens are young individuals. But
a few — such as the Zebra Shark case listed above, which was 6 feet (1.85
metres) long — were quite large and may have been reproductively mature. Yet, if
shark pigmentation patterns play a role in courtship signaling and other
agonistic displays, it seems unlikely that an albino shark would compete
effectively against 'normally' pigmented members of their own species.